The objective of the proposed research is to undertaken a comparative analysis of antecedents of changes in rates of homicide in roughly 110 nations for the period 1900-1970. The proposed research is now made possible by the existence of a new Comparative Crime Data File (CCDF) containing data on rates of homicide and other offenses in roughly 110 nations. This data file was assembled over a three-year period. The analysis will focus on the possible effects of three different classes of antecedents: (1) short-term societal events--like recessions, wars, periods of political instability, and rapid changes in unemployment and other indices of national well-being; (2) long-term social changes--like modernization, urbanization, industrial development, and demographic changes; and (3) relatively static aspects of social structure--like resource distribution, family structure, inequality and poverty, and general standard of living. An analysis of the effects of these three classes of possible antecedents will provide the empirical basis for a comprehensive assessment of whether, and to what degree, trends in homicide rates are predictable. The results of these analyses will be used to develop a theory of homicide rate trends which rests upon a broad comparative base. Use of the 110-nation CCDF will maximize the chances of identifying general relationships which transcend the idiosyncratic forces present in individual societies, as well as relationships which may hold only for certain groups of nations.